no Federation with instances that use altered versions or proprietary versions of AP.
It’s especially funny given (the last time I checked) neither kbin nor lemmy actually followed the spec properly. They ignore the jsonld requirements and resort to field names, that, by the spec, should be dropped.
But lemmy doesn’t use “plain json”, it annotates some fields with the schema, just not all of them, which makes it a mess. You either do json-ld proper, or you don’t do it at all.